Cutting fluids, such as lubricants and coolants, are commonly used with machining tools, such as drilling machines, to facilitate the cutting operation. The cutting fluid is typically directed to the cutting portion of the tool and the material, or workpiece, being cut. In particular, the cutting fluid is typically directed to the cutting portion of the tool at the location, or worksite, where the cutter contacts the workpiece.
The cutting fluid acts as a coolant to keep the cutting portion of the cutter below the temperature at which its hardness and resistance to abrasion are reduced. The cutting fluid also keeps the workpiece cool to prevent it from warping during the cutting operation. Maintaining the cutting portion of the cutter below the critical temperature and preventing the workpiece from warping produces a clean cut and more accurate final dimensions on the workpiece.
The cutting fluid also acts as a lubricant to reduce the power consumption of the cutter, reduce wear on the cutting portion, and reduce the amount of heat generated by the cutting operation. Lubrication can also provide an improved finish on the workpiece, flush composite dust and metal chips created during the cutting operation from the worksite, and prevent corrosion of the workpiece and the cutter.
The cutting fluid may be supplied to the cutting portion of the cutter and the workpiece externally or internally. In a drilling machine, a conventional means for delivering the cutting fluid to the cutting portion of the cutter and the workpiece internally is an oil hole drill. The oil hole drill has a longitudinal bore therethrough which defines a fluid passageway for the cutting fluid. Cutting fluid from an external supply source is delivered to the cutting portion of the cutter and the workpiece through the passageway defined by the bore of the oil hole drill.
Typically, a chuck secures the oil hole drill to the rotating element, or spindle, of the drilling machine. In a conventional drilling machine adapted for use with an oil hole drill, the chuck has a radially extending opening therethrough which defines a fluid passageway for the cutting fluid. The opening is in fluid communication with the bore of the oil hole drill so that the opening of the chuck and the bore define a continuous fluid passageway for delivering the cutting fluid to the cutting portion of the cutter and the workpiece.
The opening of the chuck is surrounded by an annular sleeve, known in the art as a cutting fluid gland, which prevents leakage of the cutting fluid from the machinery joint between the chuck and the cutting fluid gland. The chuck is rotatable relative to the cutting fluid gland such that the spindle of the drilling machine rotates the chuck and the oil hole drill to accomplish the cutting operation.
The cutting fluid gland has a radially extending opening therethrough which defines a fluid passageway for the cutting fluid. The opening is in fluid communication with the opening of the chuck so that the opening of the cutting fluid gland, the opening of the chuck, and the bore of the oil hole drill define a continuous fluid passageway for delivering the cutting fluid to the cutting portion of the cutter and the workpiece.
Conventional drilling machines which include an oil hole drill typically use spaced-apart, rubberized O-rings to seal the circumferential joint between the chuck and the cutting fluid gland. A portion of the cutting fluid lubricates the O-rings and reduces the rotational friction between the chuck and the gland. The drilling machine, however, can operate at rotational speeds exceeding about 10,000 revolutions per minute (RPM). The O-rings can thus deteriorate rapidly in the high-temperature environment of the machinery joint.
Consequently, the rubberized O-rings can fail abruptly and without warning. Failure of the O-rings results in a rapid and complete loss of the cutting fluid to the cutting portion of the cutter and the workpiece. Although they are relatively inexpensive, replacement of the O-rings requires that the drilling machine be shut-down. The suspension of the cutting operation for a period of time results in a significant loss of production, particularly when the failure of the O-rings cannot be anticipated.
It is therefore an object of the invention to provide a cutter body for a machining tool which is adapted for reliably delivering a cooling and lubricating fluid to the cutting portion of the tool and a workpiece.
It is a more particular object of the invention to provide a cutter body for a drilling machine which includes a chuck and a cutting fluid gland, and which does not use conventional O-rings to seal the machinery joint between the chuck and the gland.
It is another object of the invention to provide a cutter body for a machining tool which includes a cutting fluid gland having bearing surfaces made of a self-lubricating and self-sealing material.
It is another object of the invention to provide a cutter body for a machining tool including an oil hole drill having a longitudinal bore therethrough which defines a fluid passageway for delivering a cutting fluid to the cutting portion of the tool and a workpiece.
It is another object of the invention to provide a cutter body for a machining tool including a chuck having an opening therethrough which defines a fluid passageway for delivering a cutting fluid to the cutting portion of the tool and a workpiece.
It is another object of the invention to provide a cutter body for a machining tool including a cutting fluid gland having an opening therethrough which defines a fluid passageway for delivering a cutting fluid to the cutting portion of the tool and a workpiece.
It is another object of the invention to provide a cutter body for a machining tool including a cutting fluid gland which is in fluid communication with a chuck which is in fluid communication with an oil hole drill for delivering a cutting fluid to the cutting portion of the tool and a workpiece.